Managing destruction projects
Project management has its roots in the construction industry, and construction projects of all kinds continue to play a significant role in the profession. The process of building an office tower, school, or stadium “from the ground up” is well entrenched in the folklore of project management, as these types of projects have been examined and dissected thoroughly in the literature over the years. It is fair to say that the generic construction process is well understood by now. But, at some point in time, many of the structures that we have built must be replaced or eliminated. At that juncture, we destruct what we have taken so much time to construct before. While the basic processes that govern the conduct of a construction project are well known, not much has been written about the counterpart destruction activity, at least as far as management is concerned.
Even though each demolition is a unique event, it is possible to conceive of the destruction project as a generic set of processes that culminates in the complete dissolution of an existing structure. It is recognized that destruction can take many forms, including a form that that may even include renovation or upgrading of an existing edifice. The focus in this presentation is not on these “partial” destructions. Rather, the emphasis is placed on “total” destruction in which the existing structure is demolished or “taken to the ground” by, say, wrecking ball or implosion techniques.
The specific example of an implosion is used throughout. This is done because implosion represents the most extreme case of controlled destruction in that a building that has taken several years to build can be reduced to rubble in a matter of seconds. It is also a spectacular destruction, usually drawing large crowds and extensive media coverage. Many papers and books have been written about the technology of implosion. In contrast, this paper explores implosion from a management point of view. Emphasis is placed on the planning, implementation, and termination activities associated with the implosion of a large building. Monitoring and control aspects of these projects are critical elements. And, needless to say, adoption of effective risk-management schemes is essential. References to interesting implosion Web sites are supplied as an extra-added attraction.
Although the emphasis in this paper is on the management of destruction activity, some consideration of implosion technology is appropriate. In envisioning implosion events, one’s thoughts might turn to recent demolitions of structures such as the Seattle Kingdome, the J.L. Hudson Department Store in Detroit, and the five Las Vegas hotel-casinos that have been destroyed since 1993 (Dunes, Landmark, Sands, Hacienda, Aladdin). All of these demolition projects will be featured later.
The Implosion Alternative
Why implode? As might be expected, implosion is the preferred demolition technique when it represents the safest and/or most economical approach in a given situation. For fairly obvious reasons, it is the favored approach in demolishing large buildings comprised of many floors and levels and/or buildings located in congested built-up areas. Once considered to be a rather rare approach to demolition due to its perceived risky nature, the technology has been now developed to the point where unfortunate incidents are the exception rather than the rule. Consequently, customer and community acceptance of implosion as a viable destruction technique is somewhat widespread at the moment. This is not to say that there are not unfavorable outcomes. As will be shown later, things do not always go as planned.
Implosion is a technique for achieving a controlled progressive collapse of a structure. Although explosives are used in the process, the building itself is not “blown up” as many people seem to think. Rather, small quantities of explosives (perhaps weighing only a few ounces each) are strategically placed in a way that “removes” structural supports. As these supports are removed, the force of gravity takes over and the building falls to the ground in an anticipated way (hopefully). The number and the placement of the charges depend on a number of factors assessed by the demolition team. Included among these factors are age and condition of the building, its size and design (configuration), and construction materials/technology used. A typical large structure might require several thousand separate explosive charges to bring it down, but some may require only several hundred. Once the charges are detonated, the buildings crumble in a matter of seconds. As one example, close to 6,000 gelatin dynamite explosives and over 22 miles of detonation cord were employed to fell the Seattle Kingdome in just 17 seconds.
Strategically, the goal of the detonation process is to first weaken the center of the structure so that it collapses to create an “open area” for other rubble to fall into. Then, subsequent charges are fired in the direction of the exterior walls in a precise chained-reaction pattern to achieve the desired results. The building in essence falls progressively by section in a coordinated way. This is one activity for which it can be truly said that timing is everything. Major problems can be caused by buildings that fall in the “wrong way,” and a mistake in timing can lead to that.
The implosion process described above is only one component of the overall demolition project. In fact, since implosion is a rather specialized art performed by only a handful of companies in this country (for large projects), it is typically done on a subcontract basis under a general contractor. That is, implosion services would normally be considered as a procurement by the general contractor. Implosion services do not come cheap, and can easily represent up to more than half of the overall project costs.
The usual project management processes apply. The planning, implementation, and termination stages of implosion projects are easily identified. The major difference between construction and destruction projects is, of course, that the implementation stage of the latter is quite short. The implosion itself is only one part of implementation. Also involved in that stage would be the transport (and storage) of the explosives, obtainment of the necessary permits and local support personnel, determination of the optimal explosive configuration (including testing), physical placement of the explosives, conduct of a neighborhood preparedness program, delivery of media and citizen awareness campaigns, and enforcement of follow-up cleanup activities. Since some of these tasks can be conducted in parallel, the elapsed time for all of these activities to take place could be as little as a few months for an experienced demolition contractor.
Preparatory to the implosion itself, the building must be prepared and a risk mitigation plan must be put into effect. In addition to readying the building structurally for what is to come (by weakening some of infrastructure and removing walls on lower levels), the project team “strips” the building of components that may lead to undesirable consequences as far as air pollution and public heath are concerned. Such environmental remediation, particularly as it relates to asbestos and lead components, is required by federal and state laws. As an example, demolitions must adhere to United States Environmental Protection Agency regulations embodied in its National Emissions Standards for Hazardous Air Pollutants (NESHAP) code.
During the implosion that lasts only seconds, considerable threats to human life and damages to property could potentially be at stake unless every effort is made mitigate these potential risks. (Actually, the longer does the implosion last, the greater are the risks.) Adequate controls and safeguards need to be in place so that these “external effects” are minimized. These controls typically require the efforts of not only the project team, but also inputs from the community and its government units as well (public officials, police and fire departments, hazardous waste units, and so forth). Substantial community resource inputs are, in fact, necessary at every step in the process as permits must be given in the early stages, safety and environmental concerns musts be addressed, crowds and traffic must be controlled, crimes and fires must be prevented, and cleanups must be monitored and inspected.
Undesirable but unpreventable physical outputs of the implosion process include dust and debris. These entities must be controlled. Dust spews forth in dense clouds in a way determined by the pattern of the building’s collapse and the prevailing wind. Mountains of debris pile up and must be removed, after which the area and its surroundings must be cleaned up and restored. When the Seattle Kingdome was imploded recently, dust clouds spread out all over downtown Seattle and, at the site, a pile of rubble emerged that was over 12 feet high in places. Removal and cleanup of that debris will take up to four months of effort by the contractors.
Interestingly, noise and vibrations levels of implosions generally do not cause unusual problems, as they have been shown to be usually within limits allowable by law.
Finally, undesirable but preventable physical consequences of implosions concern damages to nearby properties as well as to, possibly, life and limb of demolition workers, residential and business neighbors, and even onlookers. Even though vibration levels do not generally cause problems, they could do so in certain instances. Vibrations from the implosion have the potential for weakening and damaging nearby structures as well as community infrastructure such as roads, sidewalks, streetlights, and utility pipelines. Windows in nearby buildings may crack or shatter. Flying debris could presumably do great harm not only to buildings but also to people who may be injured by such fallout. The management plan needs to incorporate ways of mitigating all of these very important risks.
As one might expect, the risk-mitigation measures for implosion projects are rather extensive. Nobody wants to deal with the prospect of multimillion-dollar insurance claims against the project. It all starts with the transport and storage of the explosives. Trucks carrying several thousand pounds of explosives over state lines are easily noticed. Federal, state, and local statutes obviously heavily regulate such transport. Designated “safe routes” are utilized to avoid densely populated areas. As the explosives are transported to what might be a site in or near an urban area, fire department officials for the final leg of the journey typically escort the trucks. Nothing is left to chance, including storage of the explosive materials. The National Fire Protection Association (NFPA) regulates storage of explosives. Iron chambers surrounded by earthen barriers serve as holding devices. These chambers are strategically located to minimize the chance that unintended ignition would cause damage to nearby structures. They are placed on 24-hour guard by security officials.
In the preparatory phase, every effort is made to insure that the demolition will proceed in a predictable way once the charges are detonated. Blueprints of the building are studied, and where there are no blueprints, some may be manufactured. Examination and documentation of the types of building materials used, the condition of the building, and placement of the load-bearing beams and columns are undertaken. It is typical for all stairwells to be cut away, and where there are adjoining buildings, for them to be physically separated to the extent possible. In some situations, steel cables may be attached for possible use in pulling the building in a certain way once it starts to fall. And, in addition to inserting explosives in holes drilled into columns, some may be wrapped around structural support columns that have been designated as critical to a successful result.
The environmentally related pre-implosion operations for asbestos and lead have been mentioned already. This can be a very costly undertaking for older buildings.
A test series of blasts is always desirable, and usually employed unless unique conditions preclude this activity. Among other things, a test blast indicates how far debris may stray from the building when the major event occurs. In cases where the debris may travel a distance that is considered excessive, openings of the building may be covered to contain the flying rubble, or chain-link fence materials may be used to keep debris under control.
In the implementation or execution stage, worker protection and crowd control are of paramount importance. The demolition team, working with community and government officials, defines what is known as a blast or safety perimeter. Think of this as a no-trespassing zone. This is an area that is heavily controlled to insure the maximum safety for workers and citizens. Actually, two perimeters would be defined. The first or primary perimeter would exclude anyone other than personnel essential to the conduct of the blasting operation. Obviously, pedestrian and vehicle traffic is re-routed. The outer boundary of this perimeter may be anywhere from 500 to 1,000 feet away from the building site. The secondary perimeter beyond would allow the presence of pedestrians and vehicles. At this perimeter’s edge would be the area roped off for onlookers and curiosity seekers.
To minimize neighborhood impacts on property and human health, residents and businesses situated within the blast perimeter are notified about the timing of the implosion, and, as a precaution, are asked to close (but not necessarily board up) all windows, shut off all air intake devices (e.g., air conditioners), and provide covers over any vents through which dust may enter their premises. In rare instances, the demolition contractor may provide special protection for neighboring properties. This may involve the physical wrapping of buildings in special kind of plastic or erecting protective barriers of some type.
Prior to detonating the charges, the fire department may be asked to soak down lower levels of the building in order to achieve dust control, particularly on days when the prevailing winds introduce uncertainty into the dust cloud’s ultimate destination.
Now comes the time that all project managers dream about. Fire and police departments take up their positions. Media photographers and announcers jostle for the best positions. Beyond the safety perimeter, eager throngs of curiosity seekers become unusually quiet. The blaster (i.e., project manager) takes up her protected position less than 100 yards from the site. Ten, nine, eight,…, three, two, one, implosion! Accompanied by the gasps of bystanders, the first blasts are heard, the building starts on its downward spiral, and there is noise and dust everywhere. Astoundingly, everything is over within seconds. The crowd cheers, the sidewalk vendors close up shop, and everyone but the demolition teams goes home.
After the building has been imploded, demolition personnel move in quickly to assess the situation and determine if the building has been dropped completely and efficiently. Any parts of the structure left standing pose a risk of potential injury and need to be attended to as quickly as possible, particularly as they may contain explosives that escaped detonation. (In the case of the implosion of the infamous Alfred P. Murrah Federal Building in Oklahoma City, the demolition team needed to concern itself even with explosives that may have been deposited previously on the site!) Any fires that may have been ignited must be put out. When safety is assured, cleanup may begin.
Given the nature of the potential risks, the demolition sector has had a rather remarkable track record since data have been recorded. It is rare to hear about even a single injury or fatality associated with the implosion of even the largest structures and complexes, although such outcomes do occur occasionally. For example, within the last decade, the attempted explosive demolition of the Royal Canberra Hospital in Canberra, Australia, went awry, causing extensive human harm and bodily injury. Such drastic outcomes are the exception rather than the rule. (Interestingly, it is difficult to procure detailed data on injuries and fatalities in this industry, and the collection and analysis of such data is a project that I happen to be working on at the moment.)
Damages to nearby structures are far more common than human impacts. For example, implosion of the J.L. Hudson Department Store in Detroit, Michigan, on October 24, 1998, did not go according to plan. Unexpected collapse angles of several steel columns caused $4 million in damages to the city’s monorail system that ran close by. (In fairness to the demolition team, it is a wonder that this was the extent of the unanticipated damages in this city area since the unusual design and construction aspects of the building offered exceptional challenges.)
It is far more typical to hear about incidents in which the implosion did not produce the intended consequences as far as the building demolition itself is concerned. Such an outcome may or may not cause problems. One that did not cause problems occurred during the dropping of the Hacienda Hotel and Casino in Las Vegas, Nevada, on December 31, 1996. In that well-publicized case, one of the stairwells did not fall completely and was instead left partially standing and listing at an angle. That stairwell posed no immediate danger and was toppled by conventional means within an hour on the following day. A more serious impact was associated with implosion of the Jack Frost Sugar Refinery outside Philadelphia, Pennsylvania, on June 29, 1997. In that episode, initial efforts to drop the complex failed to achieve complete destruction, and part of the facility was left leaning precariously. In this case, the danger inherent in the situation was judged severe enough to warrant closing adjacent Interstate Highway 95 for a considerable length of time. As another consequence, implosion approaches to demolition were temporarily banned in the area until authorities evaluated the safety issues more carefully. The ban was not lifted until November of that year, and the portion of the facility left standing was dropped at that time. Similar occurrences took place in the attempted implosions of the Owens-Corning head house in Barrington, New Jersey, on September 22, 1999, and the head house of the Con-Agra Grain Elevator in Milwaukee, Wisconsin, on March 27, 1999. (Apparently, head houses cause unusual problems.) Both head house were brought down in second efforts on the following days, one (Owens-Corning) by mechanical means and the other (Con-Agra) with additional explosives. No immediate external danger was associated with either incident.
The aftermath of implosions may cause problems to the extent that pre-blast environmental remediation was less than totally successful. As if damage to the monorail was not enough, controversy surrounded the implosion of the J.L. Hudson Department Store in Detroit when it was alleged that lead and asbestos particles were absorbed into the air in the wake of the demolition. In that case, over $4 million was spent prior to the takedown in removing paint and insulation from the building. The controversy, including the filing of at least one lawsuit claiming unspecified injuries as a result of dust particles being emitted into the air, was quelled when measurements by public health officials showed that ambient levels of lead and asbestos were far less that those allowed by environmental authorities.
The above episodes represent isolated incidents in a long history of successful implosion projects conducted domestically and internationally. While the industry’s safety record is not perfect, and despite periodic glitches, the industry track record is outstanding considering the risks involved. The record clearly suggests that the risk-mitigation approaches mentioned in the previous section are effective as far as the direct protection of human life and physical property are concerned. The handful of major companies active in this sector of the economy justifiably prides itself on this safety record.
Demolitions by implosion are spectacular viewing events—and, rightly so. Being witness to a multiple-storied building tumbling the ground in a controlled way almost defies comprehension. Since this is the case, it is not surprising that various sites on the World Wide Web would contain implosion footage accessible via the Internet. The URLs for a few of the more interesting sites are given below:
The location <http://www.lvrj.com/lvrj_home_/in-depth/packages/onlyinvegas/implode/> is a Las Vegas Review-Journal site that provides footage of the implosions (various views) of the demolitions of the Aladdin, Dunes, Hacienda, Landmark, and Sands Hotels and Casinos.
Access to a menu of CNN “Implosions, Explosions, and Crashes” can be obtained at <http://www.cnn.com/video_vault/ implosions.html>. The razing of a New Jersey multiple-dwelling housing project is particularly interesting.
Fascinating footage of the J.L. Hudson implosion can be viewed by accessing the Web site <http://www.freep.com/news/ hudsons/index.htm>.
In addition to the above Web sites showing film of actual implosions, a search of the Web can turn up many implosion “screen savers” that can be downloaded for use at home or in the office.
Bischoff, Laura A. (1999). Planning Rikes implosion. Dayton Daily News (September 29).
Controlled Demolition, Incorporated. (2000). http://www.controlled-demolition.com
Dixon, Jennifer. (1998). State to probe implosion for safety of workers. Detroit Free Press (October 31).
Dixon, Jennifer. (1998). Test shows lead in Hudson building dust. Detroit Free Press (October 30).
Engineered Demolition, Incorporated. (2000). http://www.big-blast.com
International Society of Explosives Engineers. (1980). Blasters’ Handbook. New York.
Louderback, Joseph. (1998). Camden Fire Department manages building implosion. 9-1-1 Magazine (May/June), 20–27.
Ludwiczak, James T. (1984). The Blasting Primer. International Society of Explosives Engineers.
McMahon, Patrick. (2000). A spectacular farewell to the King. USA Today (March 27).
National Association of Demolition Contractors. (1990). Demolition. Doylestown, PA.
Puls, Mark. (1998). Asbestos, lead paint removed to minimize dust threat. Detroit Free Press (October 23).
U.S. Environmental Protection Agency. (1990). Demolition practices under the asbestos NESHAP. Code of Federal Regulations, Part 61. (November 20).
Proceedings of the Project Management Institute Annual Seminars & Symposium
September 7–16, 2000 • Houston, Texas, USA